![]() ![]() Coke is mostly produced from slot-type by-product coke ovens. = m, the combustion efficiency of coal and polyethylene blends was found be independent of the particle size of plastic used. Coke-oven gas is a valuable heating fuel that is used mainly within steel plants, for example, to fire blast-furnace stoves, to soak furnaces for semi-finished steel, to anneal furnaces and lime kilns as well as to heat the coke ovens themselves (Kaegi et al., 1993). The oxides are then reduced in a blast furnace that is 80100 feet high and about 25 feet in diameter (Figure 23.3.2 23.3. The apparent activation energy E of the reduction process without coke was 93.39 kJ/mol. The study demonstrates that waste rubber tires can be successfully co-injected with metallurgical coke in electric arc furnace steelmaking process to provide additional energy from combustion. The first step in the metallurgy of iron is usually roasting the ore (heating the ore in air) to remove water, decomposing carbonates into oxides, and converting sulfides into oxides. Replacing coke with natural gas can also significantly cut CO 2 in primary steelmaking, as can injecting hydrogen or ammonia into the BF to partly replace pulverized coal. Physical properties more ยป and VM appear to have a major effect upon the measured combustion efficiency of rubber blends. Methods such as coke dry quenching and optimizing pellet ratios, as well as BF equipment like top gas recovery turbines, reduce conventional primary route carbon emissions. The surface morphology of the 30% rubber blend revealed pores in the residual char that might be attributed to volatile evolution during high temperature reaction in oxygen atmosphere. Measurements of micropore surface area and bulk density of the chars collected after combustion support the higher combustion efficiency of the blends in comparison to coke alone. The presence of rubber in the blends may have had an impact upon the structure during the release and combustion of their high volatile matter (VM) and hence increased char burnout. In the early stage of combustion the weight loss rate of the blends is much faster compared to that of the raw coke due to the higher volatile yield of rubber. Under experimental conditions most of the rubber blends indicated higher combustion efficiencies compared to those of the constituent coke. Waste rubber tires were mixed in different proportions with metallurgical coke (MC) (10:90, 20:80, 30:70) for combustion and pyrolysis at 1473 K in a drop tube furnace (DTF) and thermogravimetric analyzer (TGA), respectively. The present study investigates the effect of addition of waste rubber tires on the combustion behavior of its blends with coke for carbon injection in electric arc furnace steelmaking.
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